Myopathy Followed by Rash in a Young Boy: Classic Signs?

A 5-year-old boy was having difficulty in walking up stairs; he complained of pain and weakness in both legs. His CPK had risen from 1252 U/L to 1400 U/L in 2 weeks. His CBC was normal. Two months later, these papules developed over his proximal and distal interphalangeal and metacarpophalangeal joints along with an erythematous rash around the eyelids.